A friend of mine asked me to look into it for his friend. His friend is running XP and has some virus that seems to not even letting him start up the computer. He says that it shuts down outta no where right after it starts to boot up. thx in adv.

BOOTCOMP compares the boot sector and partition table information on a disk with previously saved copies and will alert the user to any changes. When installed, the original BIOS interrupts are used to read the boot sector and partition table, defeating any virus whichmay be present
.

http://www.simtel.net/product.php?id=51889

BTPRT
BtPrt version 102 (btprt102.zip) , a program to detect and clean any boot sector virus.

http://www.simtel.net/product.php?id=51891

plus many more

http://www.simtel.net/category.php?id=304

lets hope your mate gets lucky depending on the virus

by looking at the problem he has it doesn't look like a bootsector virus (it also would be high unlikely, as there are none in the wild, and the old ones are/should be all detected by your av),

i think it's caused by a exploit (the first dcom one, early version also had the same symptoms)

i suggest you boot the system from another disk or from a floppy/cd-rom and simply restore it

i could olso be that in the autoexcu.bat that here is a command in it like reboot or restart

maybe create a bootable cd with nero, put an AV scaner on it and boot from the cd